It has been established that the stomach can exert profound reflex cardiovascular effects including increases in blood pressure, contractility, heart rate and systemic vascular resistance. One mechanism which initiates these reflex cardiovascular responses is passive gastric distension. The effect of distension is to stimulate mechanoreceptors closely associated with the stomach wall which then send afferent impulses primarily up the splanchnic nerves. The efferent limb of the reflex involves activation of both alpha- and beta-adrenergic receptors in the heart and peripheral vascular system. The present application proposes investigations into excitatory stimuli to the stomach including rapid vibration, active contraction and injection of circulating physiological substances including bradykinin, serotonin, prostaglandins, histamine and potassium. Since several of these substances are known to have local and reflex effects when injected into other areas of the cardiovascular system, an inferior vena (IVC) bypass will be constructed. This bypass allows substances injected into the stomach to be drained into a reservoir from the IVC while the right heart receives fresh donor blood from a second reservoir. Before and during gastric stimulation, the heart rate, arterial blood pressure, left ventricular dp/dt microtipped transducer), end-diastolic pressure and cardiac output (electromagnetic flowmeter) will be continuously monitored and comparisons of hemodynamic data will be made. These studies will not only elucidate the mechanisms that initiate gastric-cardiovascular reflexes but may, in addition, suggest a more rational approach toward the therapy of postprandial angina.